cutouts. worth it?
cutouts. worth it? are they worth the coin?? does the bottom of the car get all carboned up form the exhaust since the exhaust exits under the car? do u smell the fumes?
All I know, if it doesn't gain Hp, it sounds damn good anyways, but they are known for freeing up 5-10rwhp, even more on modded car. Some carbon will accumulate on the underside of the car, just get a turndown welded in to point it down.
i have 3 cutouts, 2 on the y-pipe, one on each side and then a 3rd on the i-pipe.
when i dyno'd. i did one with all closed, one with just the back one open and then the last one with all 3 open.
with just the back one open i gained 19rwhp and then with the other 2 open (all 3) i gained another 25rwhp.
its crazy, everybody at the dyno couldnt believe it.
when i dyno'd. i did one with all closed, one with just the back one open and then the last one with all 3 open.
with just the back one open i gained 19rwhp and then with the other 2 open (all 3) i gained another 25rwhp.
its crazy, everybody at the dyno couldnt believe it.
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
Likes: 3
From: Troy, AL
Wicket, you tellin' me you gained 44 RWHP with the cuttouts open? Sorry, gotta wave the 
flag on this one.
I gained 28 RWHP with a single cuttout open (423 RWHP) compared to running through the stock muffler (395 RWHP) which is VERY restrictive compared to most aftermarket muffs. Gee, I guess if I'd had two more cuttouts I would have been the first A4 tranny 346ci LS1 to dyno close to 450 RWHP with a 224 cam!
flag on this one.I gained 28 RWHP with a single cuttout open (423 RWHP) compared to running through the stock muffler (395 RWHP) which is VERY restrictive compared to most aftermarket muffs. Gee, I guess if I'd had two more cuttouts I would have been the first A4 tranny 346ci LS1 to dyno close to 450 RWHP with a 224 cam!
TECH Fanatic
Joined: Sep 2003
Posts: 1,570
Likes: 1
From: San Diego, CA
i feal no power increase but the sound is worth every penny... espesually under a brige or a tunnel.....it will scare the **** out of people ...i can smell it alittle but i have no cats... get it.
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Originally Posted by pdd
are they worth the coin?? does the bottom of the car get all carboned up form the exhaust since the exhaust exits under the car? do u smell the fumes?
A little
Not if you have cats
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Originally Posted by TSAEB
i have no cats...so will it still make an improvenment
Originally Posted by pdd
i have high flow cats. so will the under of the car get all blck???
Your better off switching your cats to the offroad pipes if you want power.
I run a cutout but only gain 1hp with it open compared to my Corsa..Now I run the cutout when my stock exhaust is on only.
I run a cutout but only gain 1hp with it open compared to my Corsa..Now I run the cutout when my stock exhaust is on only.
Originally Posted by Colonel
Wicket, you tellin' me you gained 44 RWHP with the cuttouts open? Sorry, gotta wave the flag on this one.
I gained 28 RWHP with a single cuttout open (423 RWHP) compared to running through the stock muffler (395 RWHP) which is VERY restrictive compared to most aftermarket muffs. Gee, I guess if I'd had two more cuttouts I would have been the first A4 tranny 346ci LS1 to dyno close to 450 RWHP with a 224 cam!
flag on this one.I gained 28 RWHP with a single cuttout open (423 RWHP) compared to running through the stock muffler (395 RWHP) which is VERY restrictive compared to most aftermarket muffs. Gee, I guess if I'd had two more cuttouts I would have been the first A4 tranny 346ci LS1 to dyno close to 450 RWHP with a 224 cam!
you can raise it as high as you want, you can look at the dyno sheet, is in my other thread in the "internal section". its the "finally dyno's my 231/237 cam w/ pp heads.
first pull was with all closed
2nd pull was with just the back one open
3rd pull was with all 3 open.
there was about 30 people there and everybody was amazed including my self. its crazy i have to admit, but it happened.
I checked again today what the cutout was worth.On my car the loss was 15hp/20tq across the rev range compared to running through my SLP dual dual..Now running my Corsa I gain no hp..
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
Likes: 3
From: Troy, AL
"first pull was with all closed
2nd pull was with just the back one open
3rd pull was with all 3 open."
I hope you take this in the helpful manner in which it's intended but here's a suggestion so that you get a more accurate understanding of what really happened.
1. Get the engine and drivetrain (drivetrain takes longer) up to normal driving temperature. This means driving it for a good half hour I would think.
2. Dyno 4 pulls with the single cuttout open. Take the highest reading.
3. Allow the engine to cool back to the starting temp of the first pull.
4. Dyno 4 pulls with all three cuttouts open. Take the highest reading.
Be sure to use a diagnostic scanner to monitor timing advance and O2 readings. Better yet, use a wideband. Keep the fuel/air mixture between 13:1 and 13.3:1.
I think you'll see that there is little to no difference in power between 1 and 3 cuttouts UNLESS you have a restriction between the 2 cuttouts and the single, such as a restrictive sized I-pipe.
2nd pull was with just the back one open
3rd pull was with all 3 open."
I hope you take this in the helpful manner in which it's intended but here's a suggestion so that you get a more accurate understanding of what really happened.
1. Get the engine and drivetrain (drivetrain takes longer) up to normal driving temperature. This means driving it for a good half hour I would think.
2. Dyno 4 pulls with the single cuttout open. Take the highest reading.
3. Allow the engine to cool back to the starting temp of the first pull.
4. Dyno 4 pulls with all three cuttouts open. Take the highest reading.
Be sure to use a diagnostic scanner to monitor timing advance and O2 readings. Better yet, use a wideband. Keep the fuel/air mixture between 13:1 and 13.3:1.
I think you'll see that there is little to no difference in power between 1 and 3 cuttouts UNLESS you have a restriction between the 2 cuttouts and the single, such as a restrictive sized I-pipe.